Vela X revisited
March 2010 90 cm Radio image of Vela X (Frail et al. 1997) . The image shows a high-intensity region emerging south from the Vela pulsar – termed the cocoon (yellow circle) – and…
Forgotten sources? HESS J1634-472 and HESS J1632-478
February 2010 Gamma-ray sky map of the regions of HESS J1634-472 and HESS J1632-478. Also included are the locations of four Fermi LAT sources (black dashed circles; the circle size indicates position uncertainty, not…
News about HESS J1858+020
January 2010 The very high energy gamma ray source HESS J1858+020 is located about 0.6 degr. off the Galactic plane, which is indicated by the dashed line. The color indicates the strength of the…
The Westerlund 1 Star Cluster
June 2009 The massive young stellar cluster Westerlund 1 (Source: Wikipedia, 2MASS/UMass/IPAC-Caltech/NASA/NSF) contains a large number of massive and hot stars. The size of the cluster is about 1′. Westerlund 1 (Wd1) is the…
HESS J1809-193 – more than one PWN?
January 2009 The very high energy gamma ray source HESS J1809-193 was discovered in a search for emission associated with pulsars in the range of the H.E.S.S. Galactic Plane Survey (Aharonian et el. 2007).…
Probing Extragalactic Background Light with 1ES 0229+200
November 2007 Model for the evolution of the luminosity of galaxies in the Universe. The plot shows the luminosity per unit volume as a function of wavelength and redshift, i.e. time. The luminosity basically…
Gamma Rays from the Distant BL Lac 1ES 0347-121
October 2007 To disentangle the processes at work in gamma-ray sources, multi-wavelength observations over a wide range of frequencies are required. In the investigation of the active galaxy 1ES 0347-121, contemporaneous observations with the …
TeV gamma rays from the core of M87
November 2006 The radio galaxy M87 viewed at radio wavelengths at different scales, successively zooming into smaller structures in the jet emerging from the supermassive black hole at the core of the galaxy. The…
Multiwavelength observations of H2356-309
January 2006 The ROTSE III robotic optical telescope on the H.E.S.S. site. ROTSE is a network of four 45 cm robotic, automated telescopes built for fast optical follow-up measurements in response to gamma ray…
The Blazar 1ES 1101-232 and the Gamma Ray Horizon
December 2005 The “gamma ray horizon” defined as the distance (measured in redshift z) over which a gamma ray of a given energy will typically propragate before interacting with a photon of the extragalactic…